Blue-collar workers, particularly in the construction trades, are more likely to smoke, smoke more heavily, and have less success in quitting compared to white-collar workers. Due to the transient nature of construction work, traditional employer-based worksite interventions are not practical for this population. Research on union-based smoking cessation interventions is promising, but more work is needed to develop simple, cost- effective interventions that can be implemented and sustained in larger union groups. This study will develop and test an innovative and sustainable intervention to increase participation in smoking cessation among union carpenters and floor layers. Using audience segmentation techniques from marketing and health communication, we will develop and deliver targeted smoking cessation messages to different sub-groups of these workers. This approach is focused but simple, and can easily be adopted by unions and trade organizations if found to be effective. The overall aim of this application is to promote smoking cessation in this high-risk group by boosting enrollment in a union-sponsored comprehensive smoking cessation program. We will use audience segmentation to create targeted messages that motivate action toward smoking cessation. After developing targeted messages, we will conduct a randomized controlled trial comparing targeted messaging based on audience segmentation versus standard smoking cessation education. All carpenters will receive information on quitting smoking, and access to comprehensive union-sponsored smoking cessation program. Carpenters in the intervention group will receive additional targeted materials to encourage enrollment in the union's smoking cessation program. The intervention will include monthly mailed messages based on audience segmentation data from our formative research among carpenters who smoke. The main study outcome is rates of enrollment in the smoking cessation program six months after the intervention. Other outcomes include quit rates, number of cigarettes smoked, and readiness to quit. Our study is based on the hypothesis that more effective smoking cessation messages can be shaped by data on attitudes and beliefs among workers. We will test whether carpenters who receive targeted messages based on audience segmentation are more likely to enroll in the union sponsored smoking cessation program, more likely to show change in readiness to quit smoking, and more likely to quit smoking.